Ejection of uniform micrometer-sized droplets from Faraday waves on a millimeter-sized water drop

This Letter reports the first observation and theoretical analysis of a new phenomenon: one large spherical water drop ejecting simultaneously a very large number of monodisperse microdroplets. An ultrasonic nozzle with multiple-Fourier horns in resonance enables controlled excitation of megahertz Faraday waves on the free water surface. The temporal instability of such waves leads to the ejection of 3.5-4.4 μm monodisperse droplets at a high rate (>4.0×10(7) droplets/sec). This is in stark contrast to the Rayleigh-Plateau instability, which ejects one droplet at a time.     

Controlled Deterministic Secure Quantum Communication Based on Quantum Search Algorithm

In this study, we propose a controlled deterministic secure quantum communication (CDSQC) protocol based on the idea of Grover’s quantum search algorithm (QSA). The proposed protocol has the following two advantages over the existing CDSQC protocols: (1) high qubit frequency and (2) less quantum memory. Moreover, the security analysis of the proposed protocol shows that any eavesdropper will be detected with a very high probability under both ideal and noisy quantum channel conditions.     

Exposure assessment and engineering control strategies for airborne nanoparticles: an application to emissions from nanocomposite compounding processes

In this study, nanoalumina and nanoclay particles were compounded separately with ethylene vinyl acetate (EVA) polymer to produce nanocomposites using a twin-screw extruder to investigate exposure and effective controls. Nanoparticle exposures from compounding processes were elevated under some circumstances and were affected by many factors including inadequate ventilation, surrounding air flow, feeder type, feeding method, and nanoparticle type. Engineering controls such as improved ventilation and enclosure of releasing sources were applied to the process equipment to evaluate the effectiveness of control. The nanoparticle loading device was modified by installing a ventilated enclosure surrounding the loading chamber. Exposures were studied using designed controls for comparison which include three scenarios: (1) no isolation; (2) enclosed sources; and (3) enclosed sources and improved ventilation. Particle number concentrations for diameters from 5 to 20,000 nm measured by the Fast Mobility Particle Sizer and aerodynamic particle sizer were studied. Aerosol particles were sampled on transmission electron microscope grids to characterize particle composition and morphology. Measurements and samples were taken at the near- and far-field areas relative to releasing sources. Airborne particle concentrations were reduced significantly when using the feeder enclosure, and the concentrations were below the baseline when two sources were enclosed, and the ventilation was improved when using either nanoalumina or nanoclay as fillers.     

A Layer-Integrated Model of Solute Transport in Heterogeneous Media

This study presents a numerical solution to the three-dimensional solute transport in heterogeneous media by using a layer-integrated approach. Omitting vertical spatial variation of soil and hydraulic properties within each layer, a three-dimensional solute transport can be simplified as a quasi-three-dimensional solute transport which couples a horizontal two-dimensional simulation and a vertical one-dimensional computation. The finite analytic numerical method was used to discretize the derived two-dimensional governing equation. A quadratic function was used to approximate the vertical one-dimensional concentration distribution in the layer to ensure the continuity of concentration and flux at the interface between the adjacent layers. By integration over each layer, a set of system of equations can be generated for a single column of vertical cells and solved numerically to give the vertical solute concentration profile. The solute concentration field was then obtained by solving all columns of vertical cells to achieve convergence with the iterative solution procedure. The proposed model was verified through examples from the published literatures including four verifications in terms of analytical and experimental cases. Comparison of simulation results indicates that the proposed model satisfies the solute concentration profiles obtained from experiments in time and space.     

Point Singularities of 3D Stationary Navier–Stokes Flows

This article characterizes the singularities of very weak solutions of 3D stationary Navier–Stokes equations in a punctured ball which are sufficiently small in weak L ³.     

Simple model for predicting microchannel heat sink performance and optimization

A simple model was established to predict microchannel heat sink performance based on energy balance. Both hydrodynamically and thermally developed effects were included. Comparisons with the experimental data show that this model provides satisfactory thermal resistance prediction. The model is further extended to carry out geometric optimization on the microchannel heat sink. The results from the simple model are in good agreement as compared with those obtained from three-dimensional simulations.     

Noise mapping in urban environments: A Taiwan study

This study analyzed the spatial characteristics of urban environmental noise by using noise maps produced at 345 noise monitoring stations in Tainan, Taiwan. Noise data were collected at varying intervals: morning, afternoon, and evening in both summer and winter. The spatial distributions of the noise levels during each time interval were evaluated and visualized by geographic information systems. The analytical results indicated that the highest and lowest average noise levels were 69.6 dB(A) and 59.3 dB(A) during summer mornings and winter evenings, respectively. Comparison of monitored noise levels with regulatory standards revealed that noise standard violations, which usually occur on summer evenings, are as high as 23 dB(A). Furthermore, the results of noise exposure analysis showed that over 90% of the Tainan City population are exposed to unacceptable noise as defined by US Department of Housing and Urban Development. The findings of this study show that noise maps can be useful for investigating noise in urban environments.     

The use of grey relational analysis to determine laser cutting parameters for QFN packages with multiple performance characteristics

This paper reports an application of the grey relational analysis (GRA) to directly optimize laser cutting of a quad flat non-lead (QFN) strip using six performance characteristics. The most important performance characteristics include the cutting depth, the width of heat affected zone (HAZ), and the width of cutting line for both epoxy and Cu+epoxy materials along the cutting path. During the GRA, higher grades are obtained from any of the deeper (more complete) cutting depth, reduced widths of the HAZ and reduced widths of the cutting line. From nine experiments based on the orthogonal array of L9(3⁴), a current of 29 A, a frequency of 2 kHz, and a cutting speed of 2 mm/s were found to be the best parameters for laser cutting of a QFN strip with a thickness of 0.9 mm. Moreover, the analysis of variance (ANOVA) is also employed to determine the contribution of each control parameter on the cutting quality characteristics. The three largest measured contributions on the cutting quality in decreasing order are the frequency, the current, and the cutting speed. Compared with the Taguchi optimization method, the GRA approach is significantly simpler because it directly assigns appropriate weighting factors to the required qualities. Finally, confirmation experiments are performed to ensure the robustness of the GRA predicted optimal configuration for laser cutting a QFN strip.     

Measurement of free hydroxytyrosol in microdialysates from blood and brain of anesthetized rats by liquid chromatography with fluorescence detection

Hydroxytyrosol [4-(2-hydroxyethyl)-1,2-benzenediol] is a well known natural polyphenolic component with antioxidative effects from olive oil and an aglycone of acteoside. In order to examine the in vivo metabolism of acteoside to hydroxytyrosol and the distribution of hydroxytyrosol in the blood and brain, microdialysis coupled to a liquid chromatographic system was developed to evaluate the pharmacokinetics of free-form hydroxytyrosol in rat blood and brain. Probes were implanted in the jugular vein and the brain hippocampus for blood and brain sampling purposes. Hydroxytyrosol in the microdialysis samples was separated by a reversed-phase C18 column and eluted with a mobile phase containing acetonitrile – 2% acetic acid (pH 2.6) (12:88, v/v), using a flow rate for the mobile phase of 1 mL/min. Fluorescence detection for hydroxytyrosol was set at 281 nm and 316 nm for excitation and emission wavelengths, respectively. Hydroxytyrosol and endogenous interference could be resolved within 10 min by the developed chromatographic method. The results indicated that acteoside was metabolized immediately to hydroxytyrosol in vivo and eliminated rapidly from the blood, and hydroxytyrosol could enter the brain. The blood-to-brain distribution ratio was defined by dividing the area under concentration versus time (AUC) ratio of AUC_brain/AUC_blood, which represents the AUC for brain and blood. The results suggested that the P-glycoprotein was not involved in the brain efflux transport of hydroxytyrosol.     

Determination of melamine in rat plasma,liver, kidney,spleen, bladder and brain by liquid chromatography–tandem mass spectrometry

In this study, we describe a method for the analysis of melamine in rat plasma, liver, kidney, spleen, bladder, and brain using trichloroacetic acid precipitation with mixed-mode cation-exchange solid-phase extraction and hydrophilic interaction chromatography coupled to tandem mass spectrometry detection. Method validation was investigated completely, including linearity, precision, accuracy, matrix effect, extraction recovery, and carryover for the determination of melamine. The method exhibited a good linear range covering 20–500 ng/mL, and the overall precision ranged from 1.6 to 16.3%, with the accuracy varying from −7.9 to 15.1%. The mean matrix effects of melamine in rat plasma, liver, kidney, spleen, bladder, and brain ranged from 66.2 ± 6.7 to 95.5 ± 13.2%, and the mean recoveries for melamine varied from 79.8 ± 8.2 to 113.0 ± 9.6%. Rat kidney showed the highest level among the organs (192.5% of the plasma melamine level), and the average concentration of melamine in the brain was only 7.5% of the plasma melamine concentration. This work has pointed out that even with the application of two popular preparation procedures (acid precipitation and solid-phase extraction) of melamine, the matrix effect in analyzing biological samples still exists in certain kinds of matrices.